Process of producing yellow insoluble azo dyes on the fiber.



STATES PA ERWIN HOFFA, OF H6CHST-0N-THEMAIN, GERMANY, ASSIGNOR T0 FARBWERKE,

VORM. MEISTER LUGI'US & BBfiNING, OF HfiGI-IST-ON-THE-MAIN, GERMANY, A

CORPORATIQN OF GERMANY.

PROCESS OF PRODUCING YELLOW INSOLUBLE AZO DYES ON THE FIBER.-

No Drawing.

T 0 all whom it may concern:

Be it known that I, ERWIN HoFrA, Ph. D., chemist, a citizen of the Empire of Germany, residing at Htichst-on the-Main, Germany, have invented certain new and useful Improvements in the Process of Producing Yellow Insoluble A250 Dyes on the Fiber, of which the following is a specification.

I have found, that the diazotized esters of 4-nitro-2-aminobenzoic acid give on the fiber, when combined with [l-naphthol, yellow tints of excellent fastness to washing and great resistance to the action of chlorin. The dyeings thus obtained can be discharged with hydrosulfite and they are remarkable for their great resistance to the action of chlorate.

The following example illustrates my invention:- The goods are padded with [l-naphthol in a bath of the following composition, then dried, printed with the printing color indicated hereafter, washed and soaped.

Naphthol bath.-Containing one liter and composed of: gr. of (lnaphthol, 40 cc. of caustic soda lye of 22 Be. specific gravity, 20 gr. of acid ricinoleate of ammonia.

Printing c0Zor.-There are mixed to a paste:

19.6 gr. of methyl ester of 4c-nitro-2-aminobenzoic acid with there are then added Specification of Letters Patent.

cc. of hydrochloric acid of 22 'B.;

Patented Sept. 12, 1916.

Application filed. June 15, 1915. Serial No. 34,190.

150 cc. of boiling water, the whole is well stirred and cooled by adding 250 gr. of ice. ThereupOn are gradually added cc. of a nitrite solution (290 gr. per liter), the mixture is stirred for some time, the solution filtered and made up to:

500 gr. The solution is thickened with 460 gr. of tragacanth-thickening (6011000) and there are added before use &0 gr. of sodium acetate Having now described my invention, what I claim 1s soluble azo dyes on the fiber, which consists in combining on the fiber the diazotized methyl ester of i-nitro-Q-aminobenzoic acid with (Z-naphthol.

In testimony whereof I aifix my signature in presence of two witnesses.

ERWIN HOFFA. Witnesses:

MICHAEL ZIMMERMANN, K. MfiNcH.

Copies oi this patezt may be obtained for five cents each, by addressing the Commissioner of latentl,

Washington, D. O. 

